On 20/11/15 08:31, Daniel Vetter wrote:
On Thu, Nov 19, 2015 at 04:10:26PM -0800, yu.dai@xxxxxxxxx wrote:
From: Alex Dai <yu.dai@xxxxxxxxx>
There is a memory leak warning message from i915_gem_context_clean
when GuC submission is enabled. The reason is that when LRC is
released, its ppgtt could be still referenced. The assumption that
all VMAs are unbound during release of LRC is not true.
v1: Move the code inside i915_gem_context_clean() to where ppgtt is
released because it is not cleaning context anyway but ppgtt.
Signed-off-by: Alex Dai <yu.dai@xxxxxxxxx>
retire__read drops the ctx (and hence ppgtt) reference too early,
resulting in us hitting the WARNING. See the giant thread with Tvrtko,
Chris and me:
http://www.spinics.net/lists/intel-gfx/msg78918.html
Would be great if someone could test the diff I posted in there.
It doesn't work - I have posted my IGT snippet which I thought explained it.
Problem req unreference in obj->active case. When it hits that path it
will not move the VMA to inactive and the
intel_execlists_retire_requests will be the last unreference from the
retire worker which will trigger the WARN.
I posted an IGT which hits that ->
http://patchwork.freedesktop.org/patch/65369/
And posted one give up on the active VMA mem leak patch ->
http://patchwork.freedesktop.org/patch/65529/
I have no idea yet of GuC implications, I just spotted this parallel thread.
And Mika has proposed something interesting - that we could just clean
up the active VMA in context cleanup since we know it is a false one.
However, again I don't know how that interacts with the GuC. Surely it
cannot be freeing the context with stuff genuinely still active in the GuC?
Regards,
Tvrtko
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